This article is from the Calendars FAQ, by Claus Tondering email@example.com with numerous contributions by others.
The Persian calendar is a solar calendar with a starting point that
matches that of the Islamic calendar. Its origin can be traced back to
the 11th century when a group of astronomers (including the well-known
poet Omar Khayyam) created what is known as the Jalaali calendar.
However, a number of changes have been made to the calendar since
The current calendar has been used in Iran since 1925 and in
Afghanistan since 1957. However, Afghanistan used the Islamic calendar
in the years 1999-2002.